In party-list proportional representation systems, an election threshold is a clause that stipulates that a party must receive a minimum percentage of votes, either nationally or within a particular district, to obtain any seats in the parliament. The effect of the threshold is to deny small parties the right of representation or force them into coalitions, with the presumption of rendering the election system more stable by keeping out radical factions. It is also argued that in the absence of a preferential ballot system supporters of minor parties are effectively disenfranchised and denied the right of representation by someone of their choosing.

In Poland's Sejm and Germany's Bundestag (elected through the Additional member system), this threshold is 5% (or 3 constituency seats in the Bundestag, but directly won constituencies are kept, regardless). New Zealand's House of Representatives also has a 5% threshold, but if a party wins at least one electorate seat the threshold does not apply, see Electoral system of New Zealand. The threshold is 2% in Israel's Knesset (it was 1% before 1992 and 1.5% from 1992–2003), and 10% in the Turkish parliament. In Poland, ethnic minority parties do not have to reach the threshold level to get into the parliament, and so there is always a small German minority representation in the Sejm. In Romania, for the ethnic minority parties there is a different threshold than for the national parties that run for the Chamber of Deputies.

There are also countries – such as Portugal, South Africa, Finland, the Netherlands, and the Republic of Macedonia – that have proportional representation systems without a threshold, although the Netherlands has a rule that the first seat can never be a remainder seat, which means that there is an effective threshold of 100% divided by the total number of seats. In the Slovenian parliamentary elections of 1992 and 1996 the threshold was set at 3 parliamentary seats. This meant that the parties needed to win about 3.2% of the votes in order to pass the threshold. In 2000 the threshold was raised to 4% of the votes.

In Sweden, there is a nationwide threshold of 4%, but if a party reaches 12% in one election district, it will be represented even if it does not reach the 4% level nationally. However, through the 2010 election, nobody has been elected based on the 12% rule. In Norway the nationwide electoral threshold of 4% applies only to leveling seats. A party with sufficient local support may still win the regular district seats, even if the party fails to meet the threshold. Following the 2009 election, the Liberal Party won two seats in this manner.

In Australia, which uses a single transferable voteproportional representation system, they avoided the need for an electoral threshold by establishing smaller electorates with each multi-member electorate returning fewer members of a Parliament and as such requiring a higher quota percentage in order to be elected. As Australia also uses a preferential voting system supporters of minor parties are not disenfranchised as their votes are redistributed to other candidates according to the voter's nominated order of preference which can then form part of another candidates winning quota.